Gerard Meszaros advises on using the right abstraction level and automation tools when creating unit or system-level tests.
Stuart Sierra introduces some general guidelines for designing systems which make their data and abstractions more transparent to developers, using code examples in Clojure.
Jim Duey surveys several abstraction techniques that can help in writing reusable code in Clojure.
Ola Bini attempts to answer a few questions: Why are new languages still being created, Is it worth choosing languages strategically, and Does language actually matter?
David Nolen critiques the tools, languages and methodologies used today from the perspective of solving the “mapping dilemma”, introducing match, a pattern matching library for Clojure.
Alex Miller presents some of the abstractions that make Clojure a great language: Collections, Sequence and Higher Order Functions, Multimethods, Protocols, Atoms, Macros, and others.
Marius Eriksen considers that leaky abstractions lead to scalability issues, while those providing narrow access to explicit resources - map-reduce, shared-nothing web apps, big table - scale better.